Organic Chemistry Reaction Mechanisms
Background Inductive Effect It is a permanent effect , in which an electronegative or electropositive group attached to a carbon chain , tries to pull or push the electron towards itself. If the Electronegative Group pulls electron density towards itself it is called - I effect . If the Electropositive Group pushes the electron density towards the Carbon chain , it is called as + I effect . The pulling or pushing process develops a "slight" ' positive or negative charge . Remember : Electronegative Group : - I effect Electropositive Group :- + I effect Electromeric Effect Mesomeric Effect Hyperconjugation Effect The higher the degree of Carbon atom ; the more is the hyerconjugation ffect . Nucleophilicity '''Hard Nucleophiles '''are highly unstable and reactive . e.g. Hydrogen (-1 charge ; low atomic size) '''Soft Nucleophiles ' are less unstable and less reactive . e.g. Chlorine (-1 charge ; large atomic size) The nucleophilicity is decided by its electron charge density . SN1 Reactions Basic Understanding : Reaction takes place in two steps : 1) breaking of bond 2) Making of bond . The slowest step among the two is the Rate Determining Step . The process of solvation releases energy for breaking the bond . The nucleophile will pull the electron density from Carbon and acquire -1 charge . Carbon acquires +1 charge . The cleavage of bond happens only in presence of energy . The formation of Carbocation is exothermic in nature . Therefore , there is rise in energy to break the bond , then there is drop in energy as the process is exothermic . When the bond is broken in the first step , energy is gained , this energy is then liberated to form a bond with the attacking reagent . When the leaving group leaves , carbocation is formed ; thus we have the order of stability :- Stability : Reaction favored by stable reagents . CH3 < 1o < 2o < 3o SN2 Reactions Basic Understanding : Reaction takes place in one step : 1) Breaking and making of bond takes place simultaneously . It is the only Rate determining step . The reagent attacks the anti-bonding Molecular orbital of the less stable atom and the electron density starts shifting towards it ; which results in breaking of the old bond . The Nucleophilicity of the attacking reagent and nature of the removed group determine the rate of the reaction . The attacking reagent should be more unstable , so that it attacks easily ; and the leaving group should be more stable , so that it leaves easily . The process of particles of a solvent surrounding the solute is called as Solvation . If the reaction is taking place in a solution , then the nature of the solvent also decides the rate of reaction . When a nucleophile is present in a solvent , the solvent particles surround it . The solvent particles form thick layers if the solvent is more polar . Thus , the nucleophile finds it more difficult to donate its electron to another empty orbital . Thus , more the polarity of solvent , lesser will be the rate of reaction . The attacking reagent will attack the unstable group , while the stable group will leave the parent compound . Stability : Reaction is favored by unstable reagents . ... The reagent cannot attack from both the sides. CH3 >1o > 2o > 3o Single Bond > Double Bond > Triple Bond (Due to electron cloud density) Open Chain > Closed Chain > Benzene E1 Reactions E2 Reactions Organic Tests 1) Peroxide Test : Use Fe2+ and KCNS Also you can use KI and Starch to detect formation of ether peroxide . 2) Bromine Test for Alkenes : 3) Schiff Base : 4) Fehling Test : 5) Tollen's Reagent : 6) Carbylamine Test : Catalysts and Conditions # '''Reduction #* sffs #* sdas #* ad # Oxidation # Hydrolysis Category:Chemistry